Picture scanning system



April 5, 1932. H. LUX

PICTURE SCANNING SYSTEM Filed April 16, 1950 INVENTOR HEINZ LUX ATTORNEYPatented Apr. 5, 1932 UNITED STAirg HEINZ LUX, 0F BERL IN, GEEBEANY,ASSIG-NOR TO TELEFUNKEN GESELLSCI-IAFT FUR DRAHTLOSE TELEGRAPHIE III. E.Ii, 03? BERLIN, GERMANY, A CORPORATION OF GERMANY PICTURE SCAN N11? GSYSTEM".

Application filed. April 16,: 1930, Serial No.

The present invention relates to picture scanning systems and, inparticular, to a method and means by which the speed of decompositionand recomposition of the picture transmitted and received may be madesubstantially constant over the entire picture area.

Scanning or exploring means in picture transmission sets are known bothfor picture analyzers as well as for picture compositors or re-creatorswherein the explorin means are subject to a circular movement of uniformrotation, and in which the explored picture line falls along a chord ofthe circular path. The exploring means of this type may be multiple andmay be provided, for instance, upon a uniformly revolving disk, commonlytermed a sun-flower disk; and the exploring means, in accordance withthe particular purpose for which they are intended, may be given theform of slits, luminous lines, edges or blades or the like.

If these exploring elements are of rectilinear form as heretofore used,regardless of whether disposed radially or not, then, in the case ofuniform rotation thereof, the rela tive exploring speed in reference toa line or row located-in a chord of the circular path is not constant.In fact, the exploring speed in such systems will var I from one pointtothe next. Presupposing that transmitter and receiver are built perfectlysimilar, this exploring speed variance for different points, to be sure,will not result in any distortion of the picture, but it will produce anirregular distribution of the intensity upon the picture, in so far asthe zones explored at a higher rate of speed will appear dinnner or feebler, and the irregularities of the transmitter and the receiver willthen be integrated in the same sense. However, if arrangements are sochosen that one of the corresponding apparatus, say, the transmitter, ismade to operate at a uniform rate of scanning speed, while the otherone, in this instance the receiver, will not so operate, then there willoccur a distortion of the picture in addition to irregularities in thedistribution of the various light intensities. A situation of this kindwill arise, for instance, when the copy 444,665, and in Germany March13, 1929.

to be sent out is located upon a uniformly revolving drum and if thesame is explored by an axially displaced scanning element, for instance,a luminous ray or pencil, while the picture compositor or re-creatormeans is designed along lines as hereinbefore mentioned. In this case,according to this invention, perfect compensation is insurableboth asregards uniformity of intensity distribution as well as freedom fromdistortion by" that the explorer means at the receiving end are made soarcuate or curved that the ex ploring speed along a picture line or rowbecomes constant.

Therefore, among the objects of my inven tion I have sought to provide ameans by which the scanning or analyzing speeds may be constant at alltimes; to provide a system wherein the produced light values shallclosely correspond to the time values; and, to provide the utmostsimplicity of operation. Other objects and advantages will of coursesuggest themselves and become apparent from reading the followingspecification and claims in connection with the accompanying drawings,wherein, Fig. 1 represents a type of picture recorder particularlysuited to electrochemical picture reproducing systems; 2 discloses amodification of Fig l and shows a system particularly useful in opticalrecording; while Fig. 3 discloses a further modification of the systemof Fig. 1.

Now, to refer particularly to Fig. 1 disclosing a picture recorder basedupon the electrochemical principle of picture recording, there isprovided a spindle or axis 1 about which rotates disk 2 comprisin sixrecorder edges, denoted by numerals 3 t0 8 inclusive. These recorderedges are secured to the disk on radial supports or carrier'elements.The picture line is determined by a stationary edge or blade 9 overwhich the recorder paper 10 is drawn in any preferred manner as shown bythe arrow. The length of a line in this arrangement at most is equal tohalf the len 'th of the chord over the double centric angle of twoneighboring recording edges, and the curvature of the recording edges isso ascertained that inside this range the recording speed will beconstant;

The general form of construction shown by the curved recording edges ofFig. 1 is useful also for optical picture scanning as shown by way ofexample by Fig. 2, wherein a light source 11 illuminates a slitdiaphragm 12 from which the issuing light passes toward a uniformlyrevolving disk 13 which cuts out of the band of light l l an elementhaving the size of a picture pointer unit by means of regularly disposedslits 15. The shape of the slits 15 in the disk 13 is so determined thatthe opening liberated by the disk will travel across the width of theslit 1?. at a uniform rate of speed. So far as the rest of the path ofthe rays is concerned, a solution may be found in a mirror polygon 16having a number of mirrors and a rotational speed such that the pictureupon the screen 17 will be explored in a line for line manner.

In case of symmetric disposition of the rotating system in relation tothe scanning line, it is necessary to choose another curvature for thescanning elements as Well as simultaneous shifting thereof. This case isillustrated in Fig. 3 for an electrochemical picture recorder. Referringparticularly to Fig. 3 of the drawing, the numeral 18 denotes a diskrotating about the indie l9 and having sir; tracing or writing edgesdesignated by numerals 20 to 26 inclusive. These edges are mobileradially, and their shape is such that thereby, and owing to radialdisplacement, a constant recording speed with respect to the path 9 isobtained. The desired radial movement may be controlled, e. g., by astationary and conveniently shaped cam or disk 26. The recording edgesare secured upon lamination or leaf springs having in addition a guidepin or roller 27 which is made to wipe or roll over the cam surface 26,steady pressure upon the latter being insured, for instance, by tractilesprings 28.

While the invention has been above described in only a few of itspreferred forms it is of course obvious that many modifications andchanges may be made thereto. Therefore, I believe myself to be entitledto make and use any and all of these modifications in so far as theyfall fairly within the spirit and scope of the hereinafter appendedclaims.

Having now described my invention what I claim and desire to secure byLetters Patent is the following:

1. In a picture reproducing apparatus for tracing scanning paths on aline located along the chord of a circular path, a constant speed rotaryscanning device, and a plurality of elongated and curved scanningelements, of a curvature such that the linear scanning speed thereofalong said chord is uniform carried by said scanning device forproducing during the rotation of said device constant speed scanninghroughout the length of each path traced.

2. In picture reproducing apparatus for tracing scanning paths on a linelocated along the chord of a circular path, a constant speed rotaryscanning device, and a plurality of sinusoidal scanning elements carriedby said device for producing during the rotation of said device constantspeed scanning throughout the entire length of each path traced.

3. In picture reproducing apparatus for tracing scanning paths on a linelocated along the chord of a circular path, a constant speed rotaryscanning device, a plurality of sinusoidally curved scanning elementscarried by said device and arranged to extend outwardly therefrom, andmeans for causing each elemental section of said sinusoidally curvedscanning elements to trace during the rotation of said device anelemental section of said path along said chord at substantiallyconstant velocity.

4. In picture reproducing apparatus, a continuously moving recordsurface, a rotary scanning device, a plurality of curved scanningelements extending outwardly from and carried by said scanning device,said elements being so curved as to trace, at a uniform speed, ascanning path on said record surface extending substantially along thechord of a circular path, and means cooperating with said scanningdevice for causing each point of the curved scanning elements to scanonly a single elemental section of the chord traced thereby atsubstantially uniform speed.

5. In picture reproducing apparatus, a continuously moving recorddevice, a plurality of sinusoidally curved scanning elements carried bysaid device and arranged to trace a scanning path on said record surfaceextending substantially along the chord of a circular path, and meanscooperating With said scanning device for causing each point of thesinusoidally curved scanning elements to scan only a single elementalsection of the chord traced thereby.

6. In picture reproducing apparatus, a continuously moving recordsurface, a scanning device, a plurality of sinusoidally curved scanningelements carried from said scanning device and extending radiallyupwardly therefrom and arranged to scan during the rotation thereofsuccessive lines on said record surface extending along a pathcorresponding substantially to the chord of a circular path, and a camsurface cooperating with said scanning elements for causing eachelemental section of said sinusoidally curved elements to scan onlyconsecutively single elemental sections of the traced path.

7. In picture reproducing apparatus for tracing scanning paths on a linelocated along the chord of a circular path, a rotary scanning devicecomprising a plurality of sinusoidal scanning elements.

HEINZ LUX.

surface, a scanning

